Hello Forum Members,

I was performing a manual calculation as per the requirement of Client for the external pressure design of a shell.When I checked values for the 'A' & 'B' value from manual calculation as per charts in SEC II,part D tables it is not matching with the PVelite values.Anybody can help me to resolve it.

The values of D/t =285.46 & L/D=1.1811
From Manual Calc- 'A'=0.0002518 'B'=25.1795
From Pvelite 'A'=.0002335 'B'=23.3424

Dear Bipin,

I also checked the values of 'A' & 'B' by doing manual calculation and got the same values as you are getting by manual calc.

There may be glitch in PV Elite database/Calculation, PV Elite team shall check it.

Regards,

Prashant

Suggest you have a look at Coade Mechanical Engineering News, February, 1996, p20.

This gives an explanation of results obtained from the tabulated values vs. the graphed values in ASME Section II Part D.

Thank you Ross. Can anyone from Intergraph answer to my question.

As per UG-28 if the value of factor-A falls on the left side of the material line we need to calculate pressure according to the formula P=2AE/3(Do/t) but PV Elite consider the formula as P=4B/3(Do/t).

Why does PV Elite calculates pressure using the same equation for any value of factor-A?

Hi Vibin,

If you run the analysis in the main part of PV Elite you have the choice of using table G directly or you can use the exact equation to determine the strain factor A. The option is in Tools->Configuration Job Specific Parameters. The default is to use Table G.

CodeCalc does not use or pay attention to this option. It always uses the exact equation to determine factor A.

In the linear part of the stress strain diagram (external pressure chart) B is equal to AE/2. So if you do the substitution, you get the same result as shown below.

Pa = (4(AE/2)/3/(Do/t)) = (4(AE/6)/(Do/t)) = (2(AE/3)/(Do/t))

I hope this helps.